What Can This 300 Year Old French Fortress Tell Us About Green Architecture?

besancon-citadel-1 photo

Photo: GIPE under a Creative Commons license.

These days it seems that every new building is being billed as green: LEED certifications and new technologies that limit the environmental impact of lighting, water use, heating and air conditioning abound. But on a trip last weekend to Besançon, in eastern France, I visited a building that isn't LEED certified or equipped with any fancy technology, but that nonetheless showcases important principles of green architecture. The building: the Citadel of Besançon. The architect: Sébastien Le Prestre de Vauban. The client: King Louis XIV of France.

besancon-citadel-2 photo

Photo: Jess & Peter under a Creative Commons license.
Green architecture isn't all about throwing up new buildings and stuffing them with gadgets. Often, buildings that are called green are actually just stupid. The greenest brick, Lloyd reminds us, is the one that's already in the wall. It's also the one that stays in the wall, and doesn't end up in a pile of rubble.

The Citadel, designed by Vauban, Louis XIV's celebrated military architect, was built between 1668 and 1711. Besançon is the capital of the Franche-Comté region, which Louis XIV conquered and annexed to France, and the Citadel became the central defense point of the territory. Perched on Mount Etienne, one of the seven hills that surround Besançon, the Citadel takes up 27 acres (nearly 500,000 square feet), and is composed of three successive fronts, as well as a series of ramparts, ditches and watchtowers. Vauban didn't use the terms "green" or "sustainable" when planning the fortress, but his design displays some major tenets of smart, durable, design:

Green architecture works with the landscape: The geography of Besançon made the city an important military position as early as the arrival of Caesar in 58 BC. The city is surrounded on three sides by a oxbow of the Doubs River, and on the fourth side sits Mount Etienne. On Mount Etienne sits the Citadel. By capitalizing on the natural defenses provided by the landscape, Vauban saved money, time, and building materials. In a real sense, the hill and river are part of the Citadel- the part that didn't have to be built by Vauban.

besancon-citadel-3 photo

Photo: Jess & Peter under a Creative Commons license.
Green architecture is built to last: The age of the Citadel says it all. You don't build a complex of walls 15 feet thick and 60 feet high expecting it to fall apart. Over the last 300 years, the Citadel has seen plenty of repairs and upkeep, but it has also been the site of fighting, as recently as 1944. Today, the structure is as imposing as ever, and the fact that it was built three centuries ago only enhances that impression.

Green architecture uses local materials: How much more local can you get than building a fortress with the stone you excavate to dig the surrounding moats and ditches?

Green architecture can change functions: In the last three centuries, the Citadel has been used as a fortress and to hold prisoners of war, from the days of Louis XIV and Napoleon to World War II. Today, it is a major tourist site, and houses a zoo, an insectarium, an aquarium, vivariums, a noctarium, a climatorium, a pedagogical exhibit on evolution, botanical gardens, and a children's farm. It is also home to two museums: one on the Resistance movement and deportations of WWII, the other on the history and daily life of the Franche-Comté region.

Of course, there are points that make the Citadel not-so-green. It was an incredibly expensive and large structure whose purpose was to wage war and extend the domination of Louis XIV. But despite that, and despite its lack of a LEED certification and 21st century technology, the Citadel today reminds us that green design is ultimately about smart design that stands the test of time.

More on learning about architecture from the past:
New Lessons From Old Buildings
Why are Old Buildings Like Green Gadgets?
Steve Mouzon on Learning from Old Buildings

Related Content on Treehugger.com